As used herein, the term "tube" shall be used to collectively refer to pipe, tubing or the like of any length or cross-section unless otherwise specified.
It is known in the tube manufacturing industry, to provide for automatic, manual or semi-automatic (a combination of automatic and manual) handling of the tube for efficiency and ease of operation. The tube is often transferred from a runout table to a bundling station, where the tube is stacked and banded for storage and/or shipment. Tube is often stacked into stacks of a variety of shapes. For example, it is known to stack tube having a round cross section into hexagonal stacks, and square or rectangular cross section tube into square and/or rectangular stacks. Round tube is sometimes stacked into approximately square or rectangular stacks. The stacks of tube are then banded or strapped with metal or plastic strapping, or blocked with other materials such as wood. The banded stacks are easier to transport and otherwise handle than free tube. Stacking and banding or blocking may be generally referred to as "bundling".
To stack tube, it is necessary to lift and/or transfer the tubing from one location to another, such as to a framing or stack forming unit. In the past, such transfer was accomplished by a number of devices, including cranes and magnets. Magnets have proven inefficient because it is often difficult to hold the tube in a linearly oriented position, and nonmetallic tubing is, of course, not susceptible to such an operation. Cranes on the other hand are difficult to employ because they must be loaded and unloaded.
Other tube stacking apparatus known in the art have employed pivotable fork members which actually pivot downwardly to cause tube to roll or fall off of the fork. The fork is then retracted and a pawl or the like is employed to "scrape" any pipe remaining on the fork therefrom.
Many tube stacking apparatus have been required to separate tube from a supply of tube into discrete batches of a number of tube. The tube is then stacked according to the operation of the apparatus. A problem with creating discrete batches is that more room is required for the machine because a space between each batch must be provided. While the space may be small, space is still a commodity which must be conserved. Therefore, "batching" type machines have proven to present an economic and physical limitation to the use of those machines for the owners thereof.
It is often the case that one bundling station will be expected to bundle tubes of various dimensions and cross sectional configurations. A framing assembly is often provided which approximates the shape of the desired finished stack, into which the tube is transported. For example, if round tube if to be bundled into a hexagonal shaped stack, a hexagonal shaped frame assembly is required. If the same apparatus is to then be used to stack square tube into a square stack, then it has been necessary to replace the framing assembly with one that is square in shape.
The number of tube to be delivered to the framing assembly is critical. Most stacking apparatus heretofore known in the art has been provided with some means to count the number of tube actually delivered, stopping when the appropriate number of tube has been reached. Such devices often use a sensor or the like to count the tube as they pass over the sensor. This has proven somewhat difficult with stacks that have rows of tubes of varying numbers. For example, the hexagonal stack will have a first row of a certain number of tube, a second row which has one more tube than the first, and so forth to the row with the most number of tube. The subsequent rows then decrease in number of tube.
A need exists for an apparatus for stacking tube for bundling or the like, which is easily adaptable to be used for stacking the tube into a variety of stack shapes, and which efficiently delivers the correct number of tube to the stack.